The average cruising flight speed for commercial jets is around 540 mph. This is based on the most popular commercial jets in operation, the Boeing 747 family.
Some models of jets have been designed to reach much higher speeds than the average of 550 mph. Typically, these planes are designed for a limited number of passengers. One example is the Gulfstream G650 from Gulfstream Aerospace, which reaches speeds of up to 904 mph.
Large passenger planes, such as the Boeing 747-8, can hold up to 700 passengers and reach cruising speeds of 649 miles per hour.
Although it is decommissioned, the Tupolev TU 144 ran 55 flights from the 1960s to the '90s. Each flight held as many as 140 passengers and traveled at more than 1,000 mph.